RAPID CITY, SD (Nov. 16, 2017) – Researchers at the South Dakota School of Mines & Technology have completed a groundbreaking study on harmful bacteria found in two important South Dakota waterways. The research, undertaken by Ph.D. candidate Kelsey Murray, found genes related to harmful E. coli in parts of the Big Sioux River and Rapid Creek.
Public health officials often test streams and rivers for fecal coliform bacteria or E. coli, as this group of bacteria can be an indicator of pollution from animal or human waste. But, not all forms of E. coli are dangerous to humans; in-fact most are harmless. This study pioneered new testing methods that more accurately assess the public health risk from fecal contaminated waters by singling out and testing for genes associated with harmful forms of E. coli, including Shiga-toxigenic E. coli (STEC).
Murray’s research, performed under Linda DeVeaux, Ph.D., and Lisa Kunza, Ph.D., is titled “Path-STREAM: Development and Implementation of a Novel Method for Determining Potential Risk from Pathogenic Bacteria in Surface Water Environments” Path-STREAM stands for Pathogenicity Profiling: Shiga Toxins and Related E. coli Attributes identification Method.
The project included over 1000 DNA extractions from bacteria in water samples taken out of Rapid Creek and the Big Sioux River over a two-year period. The effort built a method to identify the pathogenic genes associated with STEC and other harmful bacteria in both water bodies. The research also examined how these water bodies can be a breeding ground for STEC.
This research has real implications on public health. In 2016 South Dakota topped the nation in per capita illness due to STEC. It’s unclear if these illnesses were directly related to E. coli found in the Big Sioux or Rapid Creek. But the presence of STEC in these water bodies, especially the Big Sioux River could serve as one source for the increased numbers. “Harmful E. coli genes were found in both waterways throughout the year, and interestingly, high rates of STEC infection in the clinic occurred during peak recreational use of the water bodies.” says Murray.
Researchers believe this work not only shows fecal contamination concerns in South Dakota but also forms a foundation for improving water testing methods. Path-STREAM can give a more accurate picture of health risks than the more common E. coli testing. “We should continue to be forward thinking and take advantage of the newest tools available to understand human health risks associated with recreational use of surface waters,” says Lisa Kunza, Ph.D., in the Department of Chemistry and Applied Biological Sciences at SD Mines.
Many waterways in the state of SD are listed as impaired for bacteria by the SD Department of Environment and Natural Resources, which highlights the need to practice good hygiene anytime anyone is in contact with the water. This should include washing your hands after recreational activities like fishing or kayaking on these waterways. The study also suggests it’s a good idea to avoid getting this water in your mouth, nose or ears. “What we have shown is that the material necessary to create a serious pathogen is here in our waters. If we don’t have a problem now, we will in the future,” says DeVeaux.
While the study shows that pollution in South Dakota waterways should be taken seriously, it should also be recognized that the water can still be enjoyed. “I hope the results of this research study will help inform the public about risk associated with recreational use of South Dakota waterways. With awareness of good safety practices, I will personally continue to kayak in the Rapid City area,” says Murray.